The Chicago company that makes the most popular of a slew of controversial caffeinated alcoholic beverages announced Tuesday night that it was removing caffeine and other sources of the stimulant from all of its products.

Phusion Projects said in a statement that it planned to "reformulate its products to remove caffeine, guarana and taurine nationwide. . . . Going forward Phusion will produce only non-caffeinated versions of Four Loko," the company's most popular drink.

"We have repeatedly contended - and still believe, as do many people throughout the country - that the combination of alcohol and caffeine is safe. If it were unsafe, popular drinks like rum and colas or Irish coffees . . . would face the same scrutiny that our products recently faced," said Chris Hunter, Jeff Wright and Jaisen Freeman, the company's managing partners. "We are taking this step after trying - unsuccessfully - to navigate a difficult and politically charged regulatory environment at both the state and federal levels."

Phusion previously announced that it was voluntarily ceasing sales in New York after officials there pushed to ban the beverages. The latest action came as federal officials are reportedly planning to crack down on the increasingly popular beverages, a response to alarm raised by health authorities and law enforcement officials.

The Food and Drug Administration will announce as early as Wednesday that it has determined that caffeine is an unsafe substance to add to alcoholic beverages, "effectively making products such as Four Loko, Joose, and others like them, prohibited for sale in the United States," Sen. Charles E. Schumer (D-N.Y.) said in a statement.

In addition, the Federal Trade Commission plans to notify companies making the product that "they are engaged in the potential illegal marketing of unsafe alcoholic drinks," he said.

The FTC would not comment on Schumer's statement, and the FDA would say only that the agency was still studying the issue.

"Prohibiting these drinks will literally save lives, preventing potentially deadly mayhem and overdrinking," said Connecticut Attorney General Richard Blumenthal (D), who was recently elected to the Senate and has led an effort by state attorneys general to restrict the drinks.

Pressure has built on federal officials to take action in the wake of a series of high-profile incidents, especially involving college students. Students at Central Washington University and Ramapo College in New Jersey ended up in the emergency room after consuming Four Lokos. Some had such high alcohol levels in their blood that they were treated for alcohol poisoning.

The drinks, sometimes called a "blackout in a can," contain high levels of both alcohol and caffeine, making it difficult for young people to realize how drunk they are, experts say. Consuming one Four Loko is the equivalent of drinking at least several cans of beer and a cup of coffee.

Several states have banned the drinks, and others have taken or are considering similar steps.

A year ago, the FDA sent letters to nearly 30 companies that make the beverages, notifying them that it planned to investigate the drinks' safety and legality.

In its statement, Phusion complained that "over the last several months we have been more than willing to talk with regulators and policymakers on the national, state and local levels. Our company has a history of being as cooperative as we possibly can to ensure that our products are consumed safely, responsibly and only by of-age adults."

The company said it had previously added multiple warning labels to its cans and taken other steps, including selling versions of its products with lower alcohol content.

"By taking this action today, we are again demonstrating leadership, cooperation and responsible corporate citizenship," the company stated.